1. Field of the Invention
The present invention relates to a fuel injection apparatus having a fuel injection valve for injecting fuel into a combustion chamber of an internal combustion engine, and particularly to the fuel injection apparatus provided with an in-cylinder pressure sensor which is mounted on a tip portion of the fuel injection valve and detects a pressure in the combustion chamber.
2. Description of the Related Art
Japanese Patent Laid-open Publication No. 2014-1700 discloses a control apparatus for an internal combustion engine having a fuel injection valve for injecting fuel into a combustion chamber of the engine, and an in-cylinder pressure sensor which is mounted on a tip portion of the fuel injection valve and detects a pressure in the combustion chamber. According to this apparatus, reduction in accuracy of the control based on the output signal of the in-cylinder pressure sensor is prevented by reducing a fuel injection noise generated by performing the fuel injection. Specifically, a process for replacing the detected in-cylinder pressure during a noise removal period with an estimated motoring pressure calculated one combustion cycle before, or a process for replacing the detected in-cylinder pressure during the noise removal period with a detected in-cylinder pressure obtained in the fuel cut operation, is performed.
In the above-described conventional apparatus, the process which replaces the detected in-cylinder pressure with the estimated pressure or the detected in-cylinder pressure detected in the fuel cut operation is performed for removing the fuel injection noise. Accordingly, there exists a problem that the detection accuracy of the in-cylinder pressure falls in the period during which the fuel injection noise enters the detection signal. Further, if entering of the fuel injection noise occurs in the expansion stroke, it is impossible to perform the noise removal by the signal replacing process.